This invention was made with government support. The government has certain rights in this invention.
This invention relates to microstrip antennas and, more particularly, to an array of microstrip antenna elements wherein each element is formed of a flared enlargement of an end portion of a microstrip conductor element, the end portion being at least partially developed with diverging orientation relative to a ground plane of the antenna element strip.
Microstrip antenna elements are employed in a variety of applications, including radar, communications, and electronic warfare systems The microstrip antenna elements are advantageous because they are readily constructed in a small physical size, have relatively light weight as compared to other forms of construction, facilitate the manufacturing process by virtue of the use of a dielectric substrate and photolithography of a microstrip conductor element upon the substrate, and because the microstrip antenna elements are readily connected to electrical circuitry formed on a circuit board sharing the ground plane of the microstrip antenna element.
A problem arises in that modern radar, communication, and electronic warfare systems would be operated advantageously at very wide bandwidths extending over a plurality of octaves. While numerous configurations of microstrip antenna elements have been developed, and while some of these microstrip antenna elements do have wide bandwidths, none of the presently available antenna elements, suitable for use on a phased array antenna, provide a sufficient bandwidth to optimize the capacity of the foregoing electronic systems. For example, present wide-band antenna-elements configurations are not suitable for multiple-octave bandwidth phased array applications due to poor impedance matching characteristics over the operating band. This deficiency applies not only to presently available microstrip antenna elements, but also to stripline antenna elements.